The invention relates to a weaving machine of the type of which weft insertion is effected by a fluid flow and in which a plurality of notched blades arranged closely adjacent each other in front of the reed confined a guide passage for the weft threads, said guide passage being laterally open towards the reed and being adapted to move into and out of the shed in synchronism with the reciprocation of the reed.
Weaving machines of this type provided with a weft thread guiding passage formed by notched blades which are independent of the blades of the reed, are known. It is characteristic of this type of weaving machines that the reed function and the weft guiding function are fullfilled by separate means (blades) as distinguished from another well-known type of weaving loom in which both functions are united in one element viz. the reed, which for this purpose comprises notched blades having their notches facing into the beating direction.
In both types of weaving machines, apart from a main blowing nozzle, arranged at the entrance of the weaving shed, a plurality of (needle-shaped) auziliary blowing nozzles are provided spaced across the weaving width which are adapted to enter into the weaving shed when the reed is taking its retracted position. Experiments have shown that the transport of the wefts through the weaving shed and particularly the transport speed to be attained is strongly dependent on the extent to which the transport air, which has been entered into the passage by blowing, may, from oneeauxiliary blowing nozzle to the next, escape between the adjacent blades to the atmosphere, thus relieving back pressure which would retard the jets.
In a weaving machine having the reed and weft guiding functions combined in one means there is little or no freedom with respect to the dimensions of the leak paths for the transport air from the guide passage formed by the reed blades. For in such a type of weaving machine the thickness of the blades as well as their spacing is primarily determined by the type of the warp threads as well as by the setting of the warp.
With separate reed and weft guide functions there is more freedom in this respect. Therefore in practice blades having a greater thickness are used to form a weft guide passage which is separate from the reed, which blades may be arranged at a larger or smaller mutual spacing. Sometimes hollow blades are used, and the inner space of such blades may then be used as an air feed passage for an auxiliary blowing nozzle. A further advantage of this type of weaving machine is to be seen in that the temple may be positioned closer to the beating line so that there will be less tendency for the selfedges to move inwardly than in a weaving machine having combined reed and weft guide functions.